The present invention is directed to a coupling for a flexible rotatable drive shaft and a gearbox having a fully engaged position and an intermediate engaged position.
Flexible rotatable drive shafts have been used in a variety of applications to transmit rotational force from one location to another. Traditionally, the flexible rotatable drive shaft has a male coupling for engaging a female coupling on a gearbox. When the male coupling engages the female coupling the flexible rotatable drive shaft is in a driving relationship with the gearbox. When the couplings are no longer coupled to one another the flexible rotatable drive shaft is no longer in a driving relationship with the gearbox. Thus the couplings have two positions, a fully engaged position and a disengaged position.
Flexible rotatable drive shafts have been proposed for use on agricultural seeding machines, see U.S. Pat. Nos. 718,664, and 4,779,471.
It is an object of the present invention to prove a coupling system for a flexible rotatable drive shaft having a first fully engaged position wherein the flexible rotatable drive shaft is in a driving relationship with a gearbox and a second intermediate engaged position wherein the flexible rotatable drive shaft engages the gearbox, but is no longer in a driving relationship with the gearbox.
A flexible rotatable drive shaft is provided with a first male coupling that is received in a second female coupling located on a gearbox. The male coupling has two circumferential grooves that define a first fully engaged position and a second intermediate engaged position. An O-ring seal is positioned between the two circumferential grooves. A male drive member protrudes axially outward from the flexible rotatable drive shaft and engages a female drive member on the gearbox when the male coupling is in its fully engaged position. In both engaged positions the male coupler is mounted to the gearbox and the O-ring seal is in contact with the female coupler sealing the gearbox housing into which the male coupler is mounted.
The female coupler is provided with a latch pin for selectively engaging the first and second circumferential grooves. The latch pin is provided with a circumferential surface for engaging the grooves and latching the flexible rotatable drive shaft to the gearbox by engaging the selected circumferential groove. The latch pin is also provided with a recessed section for unlatching the flexible rotatable drive shaft from the gearbox. In a first embodiment the circumferential surface of the latch pin is rotated into and out of engagement with the circumferential grooves. In a second embodiment, circumferential surface of the latch pin slides into and out of engagement with the circumferential grooves.